The present invention relates to apparatus for removing sheets from a stack of sheets, and more particularly to improvements in apparatus which can be utilized to singularize stacked dielectric receptor sheets for latent images which are applied thereto in radiographic apparatus. Typical examples of such sheets are polyester sheets which are to be exposed to object-modulated X-rays in the gas-filled interelectrode gap of an ionography imaging chamber. The invention also relates to radiographic apparatus which embody the improved singularizing apparatus.
A radiographic apparatus which images objects onto dielectric sheets is disclosed in commonly owned U.S. Pat. No. 4,061,915 granted Dec. 6, 1977 to Pfeifer et al. Such apparatus can utilize discrete dielectric receptor sheets or receptor sheets which are mounted on flexible carriers consisting of polyethylene. Latent images which are obtained on exposure of receptor sheets to object-modulated X-rays are thereupon converted into visible images by resorting to a liquid developing agent or to toner particles and a fusing device in a manner as disclosed, for example, in the aforementioned U.S. Pat. No. 4,061,915 to Pfeifer et al.
The commonly owned copending application Ser. No. 866,036 of Bauer et at. (whose disclosure is incorporated herein by reference) describes and claims a sheet feeding apparatus with two levers one of which carries a battery of suction heads and is pivotally coupled to the other lever to flex the upper marginal portion of the outermost sheet of a stack away from the next-to-the-outermost sheet before the other lever moves the one lever to a position in which the fully separated outermost sheet is located in the range of advancing rolls for transport of the sheet into the interelectrode gap of the imaging chamber. The just described sheet feeding apparatus insures reliable transfer of discrete sheets from the stack into the range of advancing rolls regardless of the stiffness or lack of stiffness of sheets and without defacing, scratching or otherwise damaging the sensitive surfaces of such commodities.